feat: fix execution verification (#2433)

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## Overview

Simpler version of #2377, was
reverted in #2394

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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Bug Fixes**
* Improved block validation to enforce stricter checks on block
timestamp and application hash consistency.
* Enhanced error messages for validation failures to provide clearer
feedback.

* **Tests**
* Re-enabled tests to verify block timestamp and application hash
validation during block processing.

* **Refactor**
* Simplified transaction execution logic for improved performance by
removing unnecessary locking during forkchoice state creation.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: Manav-Aggarwal

block/manager.go

@@ -800,17 +800,16 @@ func (m *Manager) execValidate(lastState types.State, header *types.SignedHeader
 	}
 
 	// // Verify that the header's timestamp is strictly greater than the last block's time
-	// headerTime := header.Time()
-	// if header.Height() > 1 && lastState.LastBlockTime.After(headerTime) {
-	// 	return fmt.Errorf("block time must be strictly increasing: got %v, last block time was %v",
-	// 		headerTime.UnixNano(), lastState.LastBlockTime)
-	// }
-
-	// // Validate that the header's AppHash matches the lastState's AppHash
-	// // Note: Assumes deferred execution
-	// if !bytes.Equal(header.AppHash, lastState.AppHash) {
-	// 	return fmt.Errorf("app hash mismatch: expected %x, got %x", lastState.AppHash, header.AppHash)
-	// }
+	headerTime := header.Time()
+	if header.Height() > 1 && lastState.LastBlockTime.After(headerTime) {
+		return fmt.Errorf("block time must be strictly increasing: got %v, last block time was %v",
+			headerTime, lastState.LastBlockTime)
+	}
+
+	// AppHash should match the last state's AppHash
+	if !bytes.Equal(header.AppHash, lastState.AppHash) {
+		return fmt.Errorf("appHash mismatch in delayed execution mode: expected %x, got %x", lastState.AppHash, header.AppHash)
+	}
 
 	return nil
 }

block/manager_test.go

@@ -575,28 +575,26 @@ func TestManager_execValidate(t *testing.T) {
 		require.NoError(err)
 	})
 
-	// TODO: https://github.com/rollkit/rollkit/issues/2250
-
-	// t.Run("non-monotonic block time with height > 1", func(t *testing.T) {
-	// 	state, header, data, privKey := makeValid()
-	// 	state.LastBlockTime = time.Now().Add(time.Minute)
-	// 	state.LastBlockHeight = 1
-	// 	header.BaseHeader.Height = state.LastBlockHeight + 1
-	// 	data.Metadata.Height = state.LastBlockHeight + 1
-	// 	signer, err := noopsigner.NewNoopSigner(privKey)
-	// 	require.NoError(err)
-	// 	header.Signature, err = types.GetSignature(header.Header, signer)
-	// 	require.NoError(err)
-	// 	err = m.execValidate(state, header, data)
-	// 	require.ErrorContains(err, "block time must be strictly increasing")
-	// })
-
-	// t.Run("app hash mismatch", func(t *testing.T) {
-	// 	state, header, data, _ := makeValid()
-	// 	state.AppHash = []byte("different")
-	// 	err := m.execValidate(state, header, data)
-	// 	require.ErrorContains(err, "app hash mismatch")
-	// })
+	t.Run("non-monotonic block time with height > 1", func(t *testing.T) {
+		state, header, data, privKey := makeValid()
+		state.LastBlockTime = time.Now().Add(time.Minute)
+		state.LastBlockHeight = 1
+		header.BaseHeader.Height = state.LastBlockHeight + 1
+		data.Metadata.Height = state.LastBlockHeight + 1
+		signer, err := noopsigner.NewNoopSigner(privKey)
+		require.NoError(err)
+		header.Signature, err = types.GetSignature(header.Header, signer)
+		require.NoError(err)
+		err = m.execValidate(state, header, data)
+		require.ErrorContains(err, "block time must be strictly increasing")
+	})
+
+	t.Run("app hash mismatch", func(t *testing.T) {
+		state, header, data, _ := makeValid()
+		state.AppHash = []byte("different")
+		err := m.execValidate(state, header, data)
+		require.ErrorContains(err, "appHash mismatch in delayed execution mode")
+	})
 }
 
 // TestGetterMethods tests simple getter methods for the Manager

execution/evm/execution.go

@@ -191,13 +191,11 @@ func (c *EngineClient) ExecuteTxs(ctx context.Context, txs [][]byte, blockHeight
 		ts = prevTimestamp + 1 // Subsequent blocks must have a higher timestamp.
 	}
 
-	c.mu.Lock()
 	args := engine.ForkchoiceStateV1{
 		HeadBlockHash:      prevBlockHash,
 		SafeBlockHash:      prevBlockHash,
 		FinalizedBlockHash: prevBlockHash,
 	}
-	c.mu.Unlock()
 
 	// update forkchoice to get the next payload id
 	var forkchoiceResult engine.ForkChoiceResponse